Final rules about using empty TV channels for broadband connections should be …

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One week from now, the FCC will vote on—and presumably approve—final rules for unlicensed "white spaces" broadband. The hope is that by opening the terrific spectrum in empty TV channels to entrepreneurs, the government can create another WiFi-style success story. But what will these first white spaces deployments look like? Operating under experimental FCC licenses, trial white spaces deployments around the US show us what's possible. If you're a WiFi user who has ever been frustrated by a flaky connection, get ready for good times.

Where do you want to go today (in our corporate shuttle)?

Microsoft has been a leader in white spaces networking, devoting a Microsoft Research team to dealing with the unique network protocols needed to make the tech work. Unlike WiFi, for instance, "WhiteFi" cannot assume that any particular channel available to it is actually free to use—microphones and TV transmitters occupy many available channels and must be avoided by white space transmitters.

This is more difficult than it sounds. Imagine an access point that finds a clear space on channel 27 and begins accepting connections from client devices. But one of the client devices is one kilometer away in a location where a TV broadcast channel 27 can be faintly detected. The channel can't be used. The access point therefore needs to query all of the client devices when negotiating its data channels, making the system more complex than WiFi, which may need to worry about interference, but does not have to hop off any particular channel because of it.

Inside the shuttles

Many other similar problems confront WhiteFi, but Microsoft managed this summer to get a campus-wide deployment up and running at its Redmond campus. The company put a few white space access points around campus and then stuck antennas and radio gear in every one of its internal corporate shuttles. It sounds easy—it's just WiFi on steroids, right?—but the company says it required a special 1 square mile FCC license, improvements to the Windows network stack, nonproduction hardware, special antennas, the creation of a complex geolocation database, and a system to bridge shuttle users' WiFi connection to the shuttles' WhiteFi link.

But it worked. Each shuttle now contains a 100mW white space transmitter, and an August presentation on the system touted its "4x range compared to 2.4 GHz (Wi-Fi) with same transmit power and receiver sensitivity."

The geolocation situation

Microsoft's geolocation database, mentioned above, isn't just for Redmond's shuttle service. It's a crucial component of the national white spaces deployment order, as the FCC will apparently require all devices to query such a database before they begin transmitting. Such a database sounds simple—stick all TV transmitter locations on a map!—but actually requires insanely detailed calculations about transmission power, terrain, line-of-sight, and more.

Open spectrum in Chicago

Microsoft has made the database publicly accessible through its new "White Space Finder." Input your address and the system will show you which TV channels are available for use in your area and plot the transmitter locations on a map. This can be a bit confusing for consumers. For instance, here in Chicago, ABC broadcasts on "channel seven," but the Microsoft system shows channel seven as being one of the seven free channels available in this region. What's going on?

During the DTV transition, ABC actually migrated to channel 44 in the UHF band—though all of its branding still shows up as "channel 7" and digital TVs internally map it to that channel. In addition, the database shows a host of low-power channels and transmitters that I, as a TV watcher, would have said were clear. Several companies, including Spectrum Bridge and Google, have indicated to the FCC that they would be willing to run such a national database, and we'll learn soon just how the FCC plans to handle this (it may allow multiple database providers).

White space for rural hospitals, small towns

Speaking of Google and Spectrum Bridge, the two white space backers announced a new trial deployment of their own this week. Spectrum Bridge has been a leader here, installing the nation's first white space network in rural Claudville, Virginia last year. In February, it brought the tech to Wilmington, North Carolina, where the extended range made possible by the new spectrum means that wireless became a practical solution for the city to connect disparate sites, like ball fields and wetlands water sensors.

This week, the company teamed up with Google to install a white spaces link in an Ohio hospital. The Hocking Valley Community Hospital gets a wireless link to a local ISP; speeds are decent and the cost is (relatively) cheap when you consider the hilly terrain.

White space device vs. local TV channels

According to Google, the network has numerous uses: "First responder vehicles, hospital grounds, as well as the health department, are being equipped with high-speed wireless Internet access. Additionally, the hospital is using the network to manage its outdoor video surveillance system."

As consumer white spaces radio cards are scarce, the tech is generally being used as a backhaul link, with client computers still connecting to the network with WiFi. As more consumer gear comes to market, though, it's possible that this will change and that white spaces radio will be built directly into laptops and smartphones.

All of this will come later, though. First, the FCC needs to set the ground rules, and the experimental deployments that we've seen to date only give us hints as to how the technology will play out when opened to wide public use.